The present invention relates to a cleaning apparatus for cleaning a substrate, such as a semiconductor wafer, by using a cleaning member, while the substrate is held and rotated and a cleaning liquid is supplied onto the substrate. The present invention also relates to the cleaning member used in the above-mentioned cleaning apparatus.
FIG. 1 shows an arrangement of a substrate cleaning apparatus of the above-mentioned type. As shown in FIG. 1, the substrate cleaning apparatus comprises a substrate holding/rotating mechanism 10 for holding and rotating a substrate Wf and a cleaning member mount mechanism 20 on which a cleaning member 21 is mounted. The substrate holding/rotating mechanism 10 comprises a plurality of arms 12 (four in FIG. 1) each having a chuck 11 attached thereto for holding the substrate Wf in a horizontal position. The arms 12 are provided to be integral with a base mount 13 which is adapted to be rotated by a rotary shaft 14 in a direction indicated by an arrow A.
The cleaning member mount mechanism 20 has a pivot arm 23. A rotary shaft 22 is connected to a forward end of the pivot arm 23 and the cleaning member 21 is attached to a lower end of the rotary shaft 22. The rotary shaft 22 is adapted to be rotated by a rotating mechanism (not shown) in a direction indicated by an arrow B, thus rotating the cleaning member 21 in the same direction. Further, a pivot shaft 24 is connected to a rear end portion of the pivot arm 23 and adapted to pivotally move the pivot arm 23 in directions indicated by arrows C. The pivot shaft 24 is also adapted to vertically move the pivot arm 23 in directions indicated by arrows D.
As shown in FIG. 2(a), the cleaning member 21 comprises a cleaning element 21a made of a sponge and a holding element 21b for holding the cleaning element 21a. This cleaning member 21 is fixed to the rotary shaft 22 and the cleaning element 21a is brought into abutment with an upper surface of the substrate Wf. At the same time, a cleaning liquid is supplied from a nozzle 25 onto the substrate Wf and the rotary shaft 22 is rotated, while the pivot arm 23 is pivotally moved, to thereby clean the upper surface of the substrate Wf When a force of rotation of the rotary shaft 22 and a force of pivotal movement of the pivot arm 23 are transmitted to the cleaning element 21a, the cleaning element 21a can be detached from the holding element 21b as shown in FIG. 2(b), due to the effect of frictional force generated between the cleaning element 21a and the substrate Wf. This deteriorates a cleaning performance and, if such detachment of the cleaning element is not detected, the apparatus continues to produce insufficiently cleaned products.
In view of the above, the present invention has been made. It is an object of the present invention to provide a substrate cleaning apparatus having a cleaning element detecting sensor for detecting a presence/absence of a cleaning element of a cleaning member attached to a cleaning member mount mechanism, and which is capable of surely detecting detachment of the cleaning element during a cleaning operation and preventing continuous production of insufficiently cleaned products.
It is another object of the present invention to provide a cleaning member which is free from a problem such as detachment of a cleaning element from a holding element
In accordance with the present invention, there is provided a cleaning apparatus for cleaning a substrate, comprising: a cleaning member; a cleaning member carrier for holding the cleaning member and bringing the cleaning member into contact with a substrate to be cleaned; and a sensor for detecting a presence/absence of a cleaning member held by the cleaning member carrier. The substrate is cleaned by causing relative movement between the cleaning member and the substrate while keeping the cleaning member and the substrate in contact with each other.
By providing the cleaning member sensor, accidental detachment of the cleaning member can be surely detected. Therefore, operation of the substrate cleaning apparatus can be stopped at the time of detection of detachment of the cleaning element, thus preventing production of insufficiently cleaned products.
The cleaning apparatus may further comprises a substrate holding device for holding the substrate, the cleaning member carrier is movable between a cleaning position where the cleaning member is brought into contact with the substrate held by the substrate holding device and a retracted position where the cleaning member is out of contact with the substrate. The cleaning member sensor may be provided at the retracted position to detect a presence/absence of the cleaning member held by the cleaning member carrier positioned at the retracted position.
By this arrangement, the cleaning member sensor can be easily set to a position such that movement of the cleaning member carrier during a cleaning operation is not disturbed.
The sensor may be provided on the cleaning member carrier to detect a presence/absence of the cleaning member held by the cleaning member carrier.
The present invention further provides a substrate cleaning member for use in a substrate cleaning apparatus, the cleaning member being adapted to be held and brought into contact with a substrate for cleaning by a cleaning member carrier of the substrate cleaning apparatus. The cleaning member has a fitting portion to be held by a cleaning member carrier, the portion having a large diameter head portion and a small diameter neck portion integrally connected to the large head portion to enable the cleaning member carrier to securely hold the cleaning member by grasping the fitting portion. The substrate cleaning member may further comprises a cleaning portion integrally connected to the small diameter neck portion at an end thereof opposite to the other end at which the large diameter head portion is connected, the cleaning member has a diameter larger than that of the small diameter neck portion. Specifically, the large diameter head portion, the small diameter neck portion and the cleaning portion are each cylindrical and coaxial with each other. A corner portion of the portion of the cleaning portion to be brought into contact with a substrate may be angular in vertical cross-section. By this arrangement, an edge of the substrate can be included in the range of area to be cleaned. Since the corner portion is made angular (not curved), the range of area to be cleaned does not change even when the pressure applied to the cleaning member changes.
The cleaning member carrier of the above-stated cleaning apparatus may comprise a cleaning member holder having an inner space configured to securely receive the large diameter head portion, the small diameter neck portion and a portion of the cleaning portion adjacent to the small diameter neck portion. The cleaning member holder consists of a plurality of segments which are releasably assembled into the cleaning member for holding the cleaning member. The cleaning member holder further comprises an inner wall defining the inner space and at least one protrusion provided on the inner wall to be pressed into the cleaning member when the cleaning member has been held by the cleaning member holder.
With this arrangement, the protrusion bites into (pierce) the cleaning member. Therefore, a force of rotation of the holding elements can be surely transmitted to the cleaning element and idle rotation of the cleaning element in the holding elements can be prevented.